Method of treating wire



Oct. 3-, 1933. c. D. JOHNSON METHOD OF TREATING WIRE Filed Feb. 24, 1952Fig.1

Fig.2.

. lnv enToT Charles D. Johnson Anya Patented Oct. 3,. 1933 METHOD OFTREATING WIRE Charles D. Johnson, Worcester, Mass, assignor to JohnsonSteel &' Wire Company, Inc., Worcester, Mass, a corporation ofMassachusetts Application February 24, 1932. Serial No. 594,880

1 Claim. (Cl. 148-12) UNITED STATES PATENT. OFFICE This inventionrelates to a method of treating wire and has for its object to providean improved method of treating wire by which both the elongation and theelastic limit or yield point are increased.

The term "elongation as used in the wiremaking art refers to the amountwhich wire will stretch before it breaks. The term yield poin iscommonly used to indicate the amount which wire will stretch before ittakes a set, in other words, before it has exceeded its elastic limit.

The stretching properties or the elongation of wire can be increased bysubjecting the wire while cold to repeated flexing such as would re- 5sult in passing the wire between two rows of pins or rolls having suchrelation that the rolls or pins of one row are staggered with relationto those of the other row so that the wire is bent or flexed as itpasses between the two rows of rolls or pins. While this operation ofcold working or repeatedly flexing the wire results in increasing thestretchability or elongation of the wire yet it also has the efiect ofreducing the elastic limit or yield pointQ In other words, such workingof the wire reduces the limit or amount to which the wire can bestretched without destroying its ability to come back to its originallength after the stretching has ceased.

' In accordance with the present invention this reduction in the elasticlimit or yield point of the wire which results from mechanicallytreating the wire to increase its elongation is counteracted bysubjecting the wire to a heat treatment of a character tending toincrease the elastic llmit of the wire. I have foundthat wire which hasbeen properly worked or flexed to increase its elongation with aresultant decrease in the elastic limit will have its yield pointrestored if 0 wire is increased.

In order to give an understanding of the invention I have illustrated inthe drawing diagrammatically an apparatus by which the improved processcan be carried out.

V Fig. 1 of the drawing is a diagrammatic view of an apparatus by whichthe present invention may be practised;

Fig. 2 is a view of one of the rolls of the wirefiexing device.

In the drawing 1 indicates the wire which is to be treated in accordancewith my invention. As stated above, the first step is to subject thewireto repeated flexing operations by which the elongation orstretchability of the wire is increased. Such flexing of the wire canconveniently be done by passing the wire between-two sets of rolls orpins, the rolls or pins of each row being so arranged relative to therolls or pins of the other row that the wire will be flexed as it isdrawn between the two rows. trated in the drawing rolls are used insteadof pins, the rolls of one row being indicated at 2 and those of theother row at 3. Therolls 2 are rotatively mounted on a suitable support4 and the rolls 3' are shown as carried by a plate or base 5 which isadjustable on the support 4 so that the rolls 3 can be moved toward andfrom the rolls 2. The plate or base 5 is retained in position by screws6 which screw into the support 4 and extend through slots '7 in theplate- 5 and adjusting screws 8 may be provided for maintaining a properadjustment of the rolls 3 with relation to the rolls 2.

The rolls of the two rows have such a relation to each other that as thewire is drawn between them said wire will be flexed progressively fromone end to the other first in one direction and then the other, thisoperation resulting in increasing the elongation or stretchable qualityof the wire.

As lllus- As stated above, however, such treatment results in decreasingthe elastic limit or yield point.

After the wire has been thus mechanically treated for increasing itsstretchability then it is subjected to a temperature of from 810 F. to1300 F. for a suitable length of time, which operation increases theyield point or elastic limit, such increase being frequently sufllcientnot only to restore the elastic limit to the original point but actuallyto increase its elastic limit beyond that which the wire had before itwas subjected to the flexing operation for increasing its elongation.

Anysuitable way of giving the wire the desired herein according to whichthe wire is drawn.

through a lead bath which may be heated to the proper temperature.Experiments have shown that thistemperature is preferably at least 810F. and not over 1300 F. The exact temperature may vary somewhatdepending on the particular kind of wire which is being treated and alsoupon the extent to which it is desirable to increase the elastic limitor yield point of the wire.

The heat treatment may also be carried out by passing the wire through asuitable .oven or through a salt bath at a proper temperature, theparticular method by which the wire is subjected to this desiredtemperature being unimportant.

In Fig. 1, 9 indicates a lead bath through which the wire is passed togive it the heat treatment, said bath being kept at the propertemperature by a burner 10. The wire is held submerged in the bath bypassing under hold-down rolls 11 as usual when wire is being passedthrough a bath for the desired treatment. I

The rolls 2 and 3 which I'prefer to use are in the form of ball bearingrolls so that the wire will receive its flexing action without havingundue frictional contact with the flexing means. Each roll is shown ascomprisng the outer ring' 12 which revolves about a center member 13,there being ball bearings 14 between the two members 12 and 13. v

This invention is adapted for the treatment of wire for various useswherever it is desirable to increase the elongation of the wire withoutdecreasing the elastic limit.

I claim.

The process of treating wire to increase its elongation withoutdecreasing its yield point which consists in flexing the wireprogressively from one end to the other and repeatedly first in onedirection and then in another a suflicient number of times to increasematerially the elongation of the wire, which operation also reduces theyield point and subsequently restoring the yield point to approximatelythe original degree by subjecting the wire to a temperature between 810F. and 1300 F.

. CHAS. D. JOHNSON.

